Seeing as there were not many alignment string box options that were reasonably affordable, I decided to create my own and share with others. This jig is used to set your toe alignment. All pieces are made out of PETG with 100% infill. These pieces are made to work with 3/4" square aluminum tubing. The round pipe is 3/4" Conduit EMT tubing. There are support holes on the 'Chassis Hooks' and 'Bar Holders', they are used to support the tubing, once they have been pressed in. The holes are undersize so that you can go with whatever size you chose to use. I went with 5/16" hardware for the support holes.

The 'Square Tubing Holder' and the 'Bar Holder' pieces also have additional undersized holes, these are to hold the aluminum tubing and pipes in place. I personally drilled each hole with a 7/32 drill bit as I used M4 x 8mm heated threaded inserts. You will need 4 of each piece (NOTE: there are 2 different types of chassis hooks, use whichever works best for your application) in order to have a full front and rear set. The chassis hooks and bar holders will be a tight fit, you can either sand the areas down or just heat up the metal and press into them.

Keep in mind that you're dealing with plastic, the tolerances may not be perfect depending on your setup, salt to taste. :-)

UPDATE:

Per user request, I have also added additional pieces for metric tolerances. The metric pieces are made for 20mm OD square and round tubing. Enjoy!